1. Field of the Invention
The present invention is directed generally to systems that sense when displacement occurs and, more particularly, to a displacement sensor for long term unattended operation under demanding environmental conditions.
2. Description of the Related Art
Linear electro-dynamic machines convert linear motion of a shaft into electrical power and are used for and have further potential for demanding applications such as unattended operation of space craft power systems, other remote systems in hostile environments, and other implementations including linear coolers and linear drives. During operation, certain displacement information regarding the shaft is necessary. Unfortunately, conventional methods for sensing displacement have not been able to meet requirements raised such as for high precision sensing having low failure rates over multi-year unattended operation in hostile environments. Furthermore, imprecise displacement sensing can adversely affect related and other systems including Stirling Engine systems, down-hole oil pumps, and free-piston engines in general.